XP "Starts up" but shows no display

-When we turn on the computer, the extractor fan and CPU fan starts up.
-Keyboard lights flash once, but you can't turn them on by using caps lock.
-Green power light shows.
-DVD Drive opens and closes

We have changed the PSU, monitor cable, monitor, and used the on board graphics with our graphics card removed. Doing these has not changed anything. The monitor just says "no signal"
We have also removed the CMOS battery for a minute and put it back. This also did nothing

Hi,
How about the ram chips, try removing one by one and use them intersectively, see if it will change anything, if it doesnt, then have the processor out and fireup the board, then after, insert the processor and fire it up without the ram, all that should give u a warning alarm, then after proving that the board is fine, with those alarms, then u can instert one ram, at a go, but make sure u interchange them.If it fails, let us know for further help.

Some kind of hard disk problem. (or he O.S. that's in it). You're sure the drive is shown in the BIOS? You have checked the hard disk cable? If you have the program disc you will (hopefully) see 'hit any key to boot from CD": start the installation process: when the screen is at "what partition do you want to install Windows on" ?...........select 'repair' the O.S. Good Luck.

Hi,
That is address allocation problem in the ram, i suggest if u have another chip, then replace it with another or best way is to do a ram test, so download this software called Memtest86, unzip and burn it on a cd-rw and startup the machine with that defected ram and follow the options.if by any chance it show u errors in red, then dont waste yo time finishing the process.Just buy a new one.